Screen('DrawTexture') with blurshader seems to do nothing?

I’m interested in writing my own procedural shader and having it attached to a texture that I’d like to draw to the screen. I’ve been reading the help documentation in ProceduralShadingAPI.m and Create2DGaussianBlurShader.m, and have decided that my goal is to run something like this:

Screen('DrawTexture', win, mytexture, [], [], [], [], [], [], blurshader);

But when I make this call, I don’t see anything on the screen – as in, everything just looks black. There are no obvious errors in the console.

Here is some more info, per the posting guidelines:

  1. Psychtoolbox Version:
>> [a, b] = PsychtoolboxVersion

a =

  0×0 empty char array

b = 

  struct with fields:

        major: 3
        minor: 0
        point: 19
       string: ''
       flavor: ''
     revision: 0
    revstring: ''
       websvn: ''

  1. Platform: Windows 10

  2. Matlab Version: (R2023a) Update 3

  3. Warnings and Errors: no obvious ones.

  4. Hardware: NVIDIA GeForce RTX 3080. Driver from NVIDIA (Driver Date: 8/7/2022; Driver Version:

Thanks in advance!

Can you provide minimal code that we could run that shows the problem?